Method and device for implementing data transmission

ABSTRACT

A method of implementing data transmission is provided, which comprises: A) comparing bit by bit data to be transmitted currently with previous transmitted data, and counting to obtain total number of different bits; and B) when it is determined that the total number of different bits is more than a half of number of bits of the data to be transmitted currently, inverting the data to be transmitted currently and then converting the inverted data into a differential signal for transmission. A device of implementing data transmission is also provided. The method and device provided by embodiments of the present invention can minimize electromagnetic interference during data transmission.

TECHNICAL FIELD OF THE INVENTION

The present invention directs to a data transmission technology usingdifferential signals, in particular, to a method and device forimplementing data transmission.

BACKGROUND OF THE INVENTION

A data transmission using differential signals has been widely adoptedin computers, telecommunication equipments, consumer electronics and thelike. The differential signal uses one numeral value to representdifference between two physical quantities, and the differential signal,regardless of a data signal or a clock signal, adopts two signals, i.e.signal pair, with one signal representing positive and the other signalrepresenting negative. When level of the positive differential signal ishigher than that of the negative differential signal, the differentialsignal denotes logical “1”, and in the contrast, when the level of thenegative differential signal is higher then that of the positivedifferential signal, the differential signal denotes logical “0”.

Nowadays, the differential signals used in data transmission primarilycomprise a low voltage differential signal (LVDS), an inner systeminterface signal mini-low voltage differential signal (mini-LVDS) and areduced swing differential signal (RSDS). With respect to the innersystem interface signal, there are many other types of differentialsignal, such as point to point differential signal (PPDS), wise-BUS andthe like.

In the prior art, when carrying out data transmission through thedifferential signals, data to be transmitted is converted to adifferential signal directly and then is transmitted. In such case, ifthe number of bits for change between previous set of transmitted dataand succeeding set of transmitted data exceeds a half of length of thedata set, then the number of bit for change of the positive signal andnegative signal amplitude of the differential signal would be more thanthe number of bit for non-changed. It can be observed in most of cases,during the data transmission, the more the changed bits is, the worsethe electromagnetic interference is.

SUMMARY OF THE INVENTION

In view of the above, the main object of the present invention is toprovide a method and device for implementing data transmission which canreduce the electromagnetic interference during the data transmission.

To achieve the above object, the solution of the present invention isembodied as follows:

The present invention provides a method of implementing datatransmission, the method comprises:

-   A) comparing bit by bit data to be transmitted currently with    previous transmitted data, and counting to obtain total number of    different bits; and-   B) when it is determined that the total number of different bits is    more than a half of number of bits of the data to be transmitted    currently, inverting the data to be transmitted currently and then    converting the inverted data into a differential signal for    transmission.

Wherein the step B) further comprises:

-   when it is determined that the total number of different bits is not    more than the half of number of bits of the data to be transmitted    currently, directly converting the data to be transmitted currently    into a differential signal for transmission.

Prior to the step A), the method further comprises:

-   A0) determining the data to be transmitted currently and the    previous transmitted data.

After the comparing bit by bit is finished, the step A) furthercomprises: saving the data to be transmitted currently as the previoustransmitted data.

Data structure of the differential signal is:

-   a data beginning signal is integrated internally into the    differential data, and correspondingly, a status information bit    indicating whether the data is inverted is inserted between the data    beginning signal and transmission data; or-   the data beginning signal is transmitted separately, and    correspondingly, after the data beginning signal arrives a receiver,    the status information bit indicating whether the data is inverted    and the transmission data are transmitted in sequence; or-   the data beginning signal and the status information bit indicating    whether the data is inverted are transmitted separately and    respectively, and correspondingly, after the data beginning signal    arrives the receiver, the status information bit is transmitted, and    after the status information bit arrives the receiver, the    corresponding data is transmitted.

A device of implementing data transmission is also provided by thepresent invention, the device comprises: a transmission datadetermination module, a data processing module, a data inversion moduleand a differential signal generation module, wherein,

-   the transmission data determination module is adapted to determine    data to be transmitted currently and send the data to the data    processing module;-   the data processing module is adapted to compare bit by bit the    received data with previous transmitted data and count total number    of different bits, and when the total number of different bits is    more than a half of number of bits of the data to be transmitted    currently, send the data to be transmitted currently to the data    inversion module;-   the data inversion module is adapted to inverted the received data    and send the inverted data to the differential signal generation    module; and-   the differential signal generation module is adapted to converted    the received data into a corresponding differential signal for    transmission outward.

Wherein, the data processing module is further adapted to:

-   when the total number of different bits is not more than the half of    number of bits of the data to be transmitted currently, directly    send the data to be transmitted currently to the differential signal    generation module.

The data processing module is further adapted to:

-   after the comparing is finished, save the data to be transmitted    currently as the previous transmitted data.

Data structure of the differential data is:

-   a data beginning signal is integrated internally into the    differential data, and a status information bit indicating whether    the data is inverted is set between the data beginning signal and    transmission data; or-   the data beginning signal is transmitted separately, and after the    data beginning signal arrives, the status information bit indicating    whether the data is inverted and the transmission data are    transmitted in sequence; or-   the data beginning signal, the status information bit indicating    whether the data is inverted and the transmission data are    transmitted separately in sequence

With the method and device for implementing data transmission accordingto the embodiment of the present invention, at each time before carryingout data transmission, data to be transmitted currently is compared bitby bit with previous transmitted data, and when the total number ofdifferent bits is more than a half of the number of bits of the data tobe transmitted currently, the data to be transmitted currently isinverted and then is converted to a differential signal fortransmission, otherwise, the data to be transmitted currently isconverted directly to a differential signal for transmission. As such,it can be assured that the number of bits for change of the positive andnegative signal amplitude of the differential signal is always less thanthe number of bits for non-changed, thus the electromagneticinterference during the data transmission is reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is schematic flow chart of a method for implementing datatransmission according to the present inventions;

FIG. 2A, FIG. 2B and FIG. 2C are schematic diagrams of data structuresof differential signals according to embodiments of the presentinvention; and

FIG. 3 is a structural schematic diagram of device for implementing datatransmission according to the present invention.

DETAILED DESCRIPTION

The basic concept of the present invention is that data to betransmitted currently is compared bit by bit with previous transmitteddata, and when the total number of different bits is more than a half ofthe number of bits of the data to be transmitted currently, the data tobe transmitted currently is inverted and then is converted to adifferential signal for transmission, otherwise, the data to betransmitted currently is converted directly to a differential signal fortransmission outward.

Next, the method and device for implementing data transmission accordingto the present invention are described in connection with embodimentsand drawings.

FIG. 1 is schematic flow chart of a data transmission method accordingto an embodiment of the present inventions. As shown in FIG. 1, themethod comprises:

Step 101, data to be transmitted currently and previous transmitted dataare determined, and the determined two sets of data are compared bit bybit, the number of different bits is counted as the total number of thedifferent bits.

Wherein, how to determine the data to be transmitted currently is wellknown in the art, the details of which are omitted there.

With respect to determining the previous transmitted data, it is carriedout by saving the previous transmitted data. The previous transmitteddata denotes a set of data having been transmitted at a most closelymoment to the present moment. The transmitted data is in form of dataset or data packet in most of cases, and length of the transmitted datais not restricted and is able to be set depending on real application,however, the data length of each transmission is same, that is, thelength of the two sets of data to be compared is same.

Wherein, the present step can be realized by means of two data setregisters. For example, the two registers are a register A and aregister B, wherein the register A stores the previous transmitted dataand the register B stores the data to be transmitted currently. For eachtime after the data to be transmitted currently is determined, thedetermined data is stored into the register B. And for each time afterthe two sets of data is compared, the data to be transmitted currentlystored in the register B is sent to the register A and stored therein,as such, the data in the register A is the previous transmitted datawhen comparing for the next time.

Wherein, how to comparing the two sets of data bit by bit, and how tocount the number of different bits can be implemented using relate totechnologies in the art, the details of which are omitted here.

Step 102, it is judged whether the total number of different bits ismore than a half of the number of bits of the data to be transmittedcurrently, and if so, step 103 is performed, and if not, step 104 isperformed.

The step 103, the data to be transmitted currently is inverted.

Wherein, the inversion is to invert each bit of the logical datacorresponding to the data to be transmitted currently.

The step 104, the data to be transmitted currently is converted to adifferential signal for transmission; and, a status information bit Revis added when transmitted the different signal. The Rev indicateswhether the inversion has been made upon the transmitted data.

Here, since the data to be transmitted currently could be the inverteddata to be transmitted currently in the step 103, or the data to betransmitted currently without the inversion of the step 103, theresultant differential signal's data structure needs to be alteredcorrespondingly, in order to indicate a receiver receiving suchdifferential signal whether the received data needs to be inverted toobtain the correct data.

For example, the data structure of the differential data can be a datastructure shown in FIG. 2A, that is, when a data beginning signal isintegrated internally into the differential data, the status informationbit Rev is added between the original data beginning signal and thetransmitted data. Alternatively, the data structure of the differentialdata can be a data structure shown in FIG. 2B, that is, when the databeginning signal is not integrated internally into the differential dataand there is another individual signal, the status information bit Revis transmitted first and then the data is transmitted after thebeginning signal arrives. Further alternatively, the data structure ofthe differential data can be a data structure shown in FIG. 2C, thestatus information bit Rev is transmitted via a separate signal line,and after the data beginning data arrives the receiver, the statusinformation bit Rev is transmitted separately, and after the statusinformation bit Rev arrives at the receiver, corresponding data istransmitted. Wherein, it is not restricted here how the statusinformation bit Rev denotes whether the inversion has been made, so theimplementation can be decided according to applications. For example, itcan be set that when the status information bit Rev is 1, it denotesthat the transmitted data has been inverted, whereas when the statusinformation bit Rev is 0, it denotes that the transmitted data has notbeen inverted. In addition, the implementation of the above datastructures can be realized by related technologies in the art, thedetails of which are omitted here.

And related technologies in the art can be used to convert the data intothe differential signal, the details of which are omitted here.

FIG. 3 is a structural schematic diagram of device for implementing datatransmission according to an embodiment of the present invention. Asshown in FIG. 3, the device comprises a transmission data determinationmodule 310, a data processing module 320, a data inversion module 330and a differential signal generation module 340.

Wherein, the transmission data determination module 310 is fordetermining data to be transmitted current and sending the data to thedata processing module 320.

The data processing module 320 is for, after receiving the data,comparing bit by bit the received data to be transmitted currently withthe previous transmitted data, and counting the number of differentbits, and when the total number of the different bits is more than ahalf of the number of bits of the data to be transmitted currently,sending the data to be transmitted currently to the data inversionmodule, otherwise, sending the data to be transmitted currently to thedifferential signal generation module 340 directly. The data processingmodule 320 is also for, after comparison is finished, storing the datato be transmitted currently as the previous transmitted data for thenext data comparison.

The data inversion module 330 is for inverting the received data andsending the inverted data to the differential signal generation module340.

The differential signal generation module 340 is for converting thereceived data to a corresponding differential signal for transmission.

The above description is provided for some advantageous embodiments ofthe invention, and does not intend to limit the scope of the presentinvention in any means.

1. A method of implementing data transmission, characterized in that themethod comprises: A) comparing bit by bit data to be transmittedcurrently with previous transmitted data, and counting to obtain a totalnumber of different bits; and B) when it is determined that the totalnumber of different bits is more than a half of number of bits of thedata to be transmitted currently, inverting the data to be transmittedcurrently and then converting the inverted data into a differentialsignal for transmission, wherein the step B) further comprises: when itis determined that the total number of different bits is not more thanthe half of number of bits of the data to be transmitted currently,directly converting the data to be transmitted currently into adifferential signal for transmission, and wherein the differentialsignal has a data structure characterized in that: a data beginningsignal is integrated internally into the differential signal, andcorrespondingly, a status information bit indicating whether the data isinverted is inserted between the data beginning signal and the data tobe transmitted currently; or the data beginning signal is transmittedseparately, and correspondingly, after the data beginning signal arrivesat a receiver, the status information bit indicating whether the data isinverted and the data to be transmitted currently are transmitted insequence; or the data beginning signal and the status information bitindicating whether the data is inverted are transmitted separately andrespectively, and correspondingly, after the data beginning signalarrives at the receiver, the status information bit is transmitted, andafter the status information bit arrives at the receiver, the data to betransmitted currently is transmitted, wherein the status information bitindicating whether the data is inverted occupies one clock period of adifferential clock signal, and is transmitted as a part of differentialsignal sequence previous to the data to be transmitted currently.
 2. Themethod of claim 1, characterized in that prior to the step A), themethod further comprises determining the data to be transmittedcurrently and the previous transmitted data.
 3. The method of claim 1further comprising saving the data to be transmitted currently as theprevious transmitted data after comparing bit by bit the data to betransmitted currently with the previous transmitted data.
 4. Anapparatus comprising: a data inverter; a data transmitter that transmitscurrent data; a data processor that receives the current data andcompares the current data bit by bit with previously transmitted dataand counts a total number of different bits, and when the total numberof different bits is more than a half of number of bits of the currentdata, the data processor sends the current data to the data inverter,wherein; the data inverter inverts the current data; and a differentialsignal generator that receives the inverted current data from the datainverter and converts the inverted current data into a correspondingdifferential signal for transmission, wherein the differential signalhas a data structure characterized in that: a data beginning signal isintegrated internally into the differential signal, and a statusinformation bit indicating whether the data is inverted is set betweenthe data beginning signal and the differential signal; or the databeginning signal is transmitted separately, and after the data beginningsignal arrives, the status information bit indicating whether the datais inverted and the differential signal are transmitted in sequence; orthe data beginning signal, the status information bit indicating whetherthe data is inverted and the differential signal are transmittedseparately in sequence, wherein the status information bit indicatingwhether the data is inverted occupies one clock period of a differentialclock signal, and is transmitted as a part of differential signalsequence previous to the data to be transmitted currently.
 5. Theapparatus of claim 4, wherein when the total number of different bits isnot more than half of the number of bits of the current data, the dataprocessor sends the current data directly to the differential signalgenerator.
 6. The apparatus of claim 5, wherein after comparing thecurrent data bit by bit with previously transmitted data, the dataprocessor saves the current data as previously transmitted data.